I have a wedding band and engagement ring with the word fadi and the number 9 what's these symbols mean ?

FADI is most likely just the designer or trade mark.
Marks Stamped Inside Rings! What do the Markings and Stamps inside your ring mean? - Jewelry-Secrets.com (http://www.jewelry-secrets.com/Jewelry/Marks-Stamped-Inside-Rings/What-Do-The-Marks-Stamped-Inside-Your-Ring-Mean.html)